Power‐system level classification of voltage‐source HVDC converter stations based upon DC fault handling capabilities

Abstract

To date, numerous concepts for converter station designs for use in voltage source converter (VSC)-based highvoltage direct current (HVDC) systems have been proposed. These differ not only in converter circuit topology, sub-module design, and control scheme but also in AC-or-DC switchgear and other auxiliary equipment. In the main, the existing literature categorises these converter stations according to just the converter circuit technologies and controls. However, for the development of network codes and to enable systematic network studies, a system-focused and technology-independent classification is needed. As such a classification does not yet exist, this study proposes a new framework, which categorises VSC station designs according to their capabilities during a DC-side fault and the method by which post-fault restoration may be achieved, given that these are the main differentiating factors from a system perspective. The classification comprises six converter station types and three time-intervals through which to fully characterise a design. Many well-known forms of converters are used as case studies, and simulation results are used to exemplify the classification framework. The outcome is a generic and technology-independent way of characterising converter station designs that is useful in wider power-system analysis but also for putting proposed converter stations into context.

Multi‐vendor interoperability in HVDC grid protection: State‐of‐the‐art and challenges ahead

“…For example, an FBC can provide continuous STATCOM mode operation while connected to a faulted HVDC grid; whereas the STATCOM mode capability is considered permanently interrupted for an FFC with an ACCB (FFC+ACCB) for the same condition. In the case of an FFC with a converter‐side DCCB (FFC+DCCB), the STATCOM capability can be seen as approximately continuous in the viewpoint of the AC system dynamics if the DCCB has an ultra‐fast opening speed or fault current limiting capability [83]. Rectifying/inverting DC current control while connected to a faulted HVDC grid : These two abilities allow a converter station to maintain current control in either rectifying or inverting direction.…”

“…Second, specifying the DC fault response or DC‐FRT requirement of the converter stations is needed to fulfil the constraints from the AC system and the HVDC grid protection strategy. This is challenging because of the large variations of converter technologies in combination with switchgear or auxiliary devices [83].…”

“…A converter station, consisting of the VSC together with any AC or DC switchgear and additional circuits, can lead to widely different DC fault responses. In [83], six types of converter stations have been identified based on their capabilities during DC-side faults. These capabilities are inherent to the converter station, regardless of the adopted protection strategy.…”

Comparative Evaluation of Voltage Source Converters With Silicon Carbide Semiconductor Devices for High-Voltage Direct Current Transmission

“…Fault blocking SMs (bipolar three quadrant capable) may require additional dc-side switchgear, a circuit breaker or disconnector, to prevent the converter feeding the fault. For such converters, STATCOM capability may be interrupted temporarily [110]- [113]. Bipolar SMs also enable overmodulation capability, i.e.…”

Equal‐area criterion and analytical model for transient stability assessment of hybrid AC–DC transmission system using voltage sourced converter

“…In all those presentations, the focus has been on the transient analysis of AC power systems. To achieve high controllability and economical transmission over long distances, high-voltage direct current (HVDC) systems using voltage sourced converters (VSCs) are seen as a promising option for grid extension [4][5][6]. The availability of an equal-area criterion for combined AC and VSC-HVDC trans-mission would be very valuable.…”